was driving around today in the city, lots of start stop driving. about 2 hours into my errands I noticed that the car was losing power and surging in first and second gear over 3500 rpm in like .5 second increments. Soon as I noticed I popped the clutch and rolled while I watched the idle. It was a very stable 850, I pulled into a sideroad and brought it up for 4k rpm under no load. Checked my torque for any codes, nothing, checked my LTFT it had changed from +3 to +7 since I last looked 3 weeks ago.

Tried to drive off once again and soon as I took a right turn out of the side street at 3500 rpm and experienced the same surging and it stalled. I rolled into the next street. searched google a bit and thought it may have been my fuel pump. I started it up in 5 minutes, drove to the gas station and filled up because I must have had only 17 litres left. I was able to get home without any surging but I didn't push it past 4000 rpm the entire way home.

So, I'm thinking it's the fuel pump because it was occurring only during acceleration uphill and acceleration during turns, also filling up my tank seemed to help.

is there any way to be sure before I start throwing money at it?

07 mt

spark plugs brand new, battery under 1 year old, 2 year old yukon coils, recent oil change 10w40, all fluid levels seem ok, highest coolant temps i ever see is 215 when pushing it.

no engine code other than catless 0420

 

Does sound like fuel pump - they are a replacement item evrey 100000 kms . So if it has that many ks on it you should replace it anyway ...then see if it fixes the problem . Otherwise you could fit a fuel pressure gauge ...but that might cost as much as a new pump so ..............

 

yeah I just hit 90k kms and I premix so that could be it. thanks I'll be replacing it come monday then.

 

Yes ,your car is exhibiting classic fuel pump failure symptoms and behavior. As they get older and worn out, especially at low fuel tank levels with hard turns. My best solution was to replace my failed RX8 Series 1 pump with the improved RX8 Series 2 pump. There are DIY's on forum here on how to do that.

Also see list below:

Engine Power Loss
• chokes as revs increase
o O2 sensor failure (too rich)
o MAF failure
o MAF disconnected
o e-shaft sensor fouled
o accessory belt fraying
• high end power loss (hard fuel cut)
o Rev limit reached
• high end power loss (jerky and stumbling)
o Ignition failure
o fuel pressure loss
o e-shaft sensor fouled
• high end power loss (smooth)
o Catalytic converter clog
o air filter clog
• low end power loss (smooth)
o Engine compression loss
• low end power loss (stumbles)
o Ignition failure
o front O2 sensor failure
• revs slowly but smoothly
o O2 sensor failure (too lean)
o catalytic converter clog
o air filter clog
• sudden power drop at a specific rpm
o Intake valving actuation problem
• trouble getting to redline
o Ignition failure
o front O2 sensor failure
o catalytic converter clog
o air filter clog
o e-shaft sensor fouled
o fuel pressure loss
o MAF failure